Fuel feeding system for otto engines



Feb. 14, 1933. R. E. BRUCKNER FUEL FEEDING SYSTEM FOR OTTO ENGINES Filed Sept. 24. 1926 ROBERT E BRUCKNER h. Q55) N Patented Feb. 14, 1933 UNITED STATES PATENT OFFICE ROBERT IEABLIL BRUC'KNER, F HASTINGS-ON-HUDSON, NEW YORK, ASSIGNOR TO DOHERTY RESEARCH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELA- p in regu WARE FUEL FEEDING SYSTEM FOR OTTOENG-INES Application filed September 24, 1928. Serial No. 137,421.

' invention aims to provide a fuel feeding system wherein a relatively heavy liquid fuel may be employed in place of expensive distillate such as gasoline. In accordance with the present invention a heavy liquid fuel, such as fuel oil, under high pressure is sprayed into a mixing chamber where it is mixed with air ated amounts, the mixture passing from-the mixing chamber to the intake manifold of the engine.

some of the more important objects of the invention are, generally stated, to produce a combustible mixture while controlling the relative proportions of the mixture components or mixture ratio and while regulating the rate of feed to the engine; to provide for the maintenance of a predetermined mixture ratio under high engine speeds, and to provide means for maintaining a substantially constant or predetermined minimum spray velocity irrespective of the rate at which the fuel is supplied for spraying. Other objects of the invention will appear as the description proceeds.

In carrying out the invention, the usual carbureter is replaced by a fuel nozzle to which liquid fuel, such as fuel oil, is supplied under high pressure by any suitable means and cooperating with the fuel nozzle is a valve for regulating the discharge capacity of the nozzle. This valve so controls the discharge capacity of the nozzle that the fuel will be sprayed from the nozzle tip at a substantially constant velocity irrespective of the amount of fuel which is supplied for spraying. This valve may be controlled by suitable linkage with the valve or means which controls the delivery of fuel to the nozzlle but it is preferred that the valve be of a type which shall function under the pressure of the fuel supplied to the-nozzle whereby the valve will tend to decrease the size of the discharge opening of the nozzle as the fuel supply decreases and will tend to increase the size of the opening as the fuel supply increases. For a given size of nozzle discharge-opening the velocity of the oil issuingfrom the nozzle is obv1ouly a function of the pressure on the oil seeking to pass through the opening and the oil pressure in turn depends on the rate of supply. Hence by decreasing the discharge capacity of the nozzle sufiiciently to maintain a substantially uniform pressure on the oil seeking to pass through the nozzle the velocity of the oil issuing from the nozzle can be maintained substantially constant as a consequence of which the degree of comminution of the fuel particles will be maintained substantially the same at all times, thus insuring uniformly efiicient burning of the fuel when introduced into the engine. The air for mixing with the oil spray produced in the manner indicated is drawn into the mixing chamber into which the spray discharges prior to its passage to the engine by the suction produced by the engine and the aspirating efiect of the fuel .spray as it issues from the nozzle. The air enters the mixing chamber through a conduit the delivery capacity of which is control-led by a valve. This valve is controlled through suitable linkage with the means governing the delivery of fuel to the nozzle and may additionally be controlled by a governor responsive to the engine speed, the governor opening the air'valve sufficiently to compensate for the proportionally greater frictional resistance retarding the flow of air into the engine under high speed. Any tendency of the fuel-air mixture to become richer as the engine speed increases is thereby obviated.

It may be noted that the maintenance of the fuel-spray jet-velocity is achieved independently of the maintenance of the optimum mixture-ratio, but cooperates with the maintenance of an optimum mixture-ratio to ensure complete combustion in the enginecylindcrs. It may also be noted that regardless of the mixture ratio of fuel and air as supplied to the mixing-chamber, the actual mixture ratio from a thermodynamic standpoint is the weight of the air in the combustion-cylinders in contact with the fuel and therefore available for combustion as contrasted with the air out of contact with the fuel divided by the weight of the fuel to be burned. In other words, unless the air and fuel are intimately mixed in the mixing chamber, an intimate mixture will not be consistently maintained in the cylinders. Therefore, the maintenance of a minimum fuel-spray jetvelocit with consequent pro r comminution 0 the fuel particles an their proper mixture with the inmoving air directly assists in maintaining the optimum actual thermodynamic mixture-ratio.

For a further understanding of the invention reference is made to the detailed description based on the accom anying drawing forming part of this speci cation.

Fig. 1 is a more or less diagrammatic view, parts being in section and parts in elevation of the preferred form of the invention, and

"Fig.2 is a view illustrating an alternative form of valve for controlling the discharge capacity of the fuel nozzle.

Fig. 3 is a section on the line 3-3 of Fig. 1.

Referring to the drawing, 10 indicates the intake manifold of an internal combustion engine of the Otto type, the engine c linders and various other operative parts 0 the engine having been omitted to simplify the illustration. Connected with the manifold as by means of a conduit 12is a mixing chamber 14 in which the fuel and air are mixed prior to the passage of the mixture to the engine. It is preferred that the fuel mixture be heated prior to its entry into the engine and for this purpose the conduit 12 is conveniently provided with a casing 16 through which exhaustv gases from the engine are allowed to pass. Opening onto the mixing chamber is a fuel nozzle generally indicated at 18 through the discharge opening of which fuel is adapted to be sprayed into the mixing chamber. Air for mixing with the fuel spray enters the mixing chamber through a convoluteshapcd air intake passage 20, this passage having a number of small holes 22 uniformly distributed around the fuel nozzle in a tangential direction whereby the air will be given a whirling motion to insure a more complete mixing of the air and fuel. The air is delivered to the passage 20 through a conduit 24 the delivery capacity of which is controlled by a valve generally indicated at 26. An air cleaner 28 of any suitable type may be provided at the intake end of the air conduit 24. The air is drawn into the mixing chamber 14 by the suction of the engine assisted by the aspirating effect of the fuel spray issuing from the fuel nozzle. However, if desired a suitable pump preferably of the rotary type as indicated at 30 may be provided in the air conduit 24 in order to render the inflow of air to the mixing chamber more positive.

The li uid fuel which is supplied to the fuel nozz e for spraying is maintained under a high pressure-preferably a pressure of approximately 3000 lbs. per square inch-by means of a suitable pump generally indicated at 32, this pump preferably being of the reciprocating plunger type having at least two plungers. This pump is shown as provided with a shaft 34 by means of which it may be driven from an suitable source of power but preferably by t e engine. Oil is supplied to the pump through a conduit 36. This conduit ma be provided with a coil 38 through which t e exhaust conduit 40 from the engine extends whereby to heat the oil.

A conduit 42 connected to the delivery side of the ump delivers the oil to an oil chamber 44 in the oil nozzle 18. This conduit is preferably provided with a coil 43 through which the exhaust conduit 40 extends whereby the oil may be still further heated before it gases to the oil nozzle.

tween the oil chamber 44 and the pump 32 there is preferably provided a safety valve 46 of any suitable type which will open to by-pass some of the oil around the pump through a conduit 48 when the pressure exceeds a given value. Between the fuel nozzle 18 and safety valve 46 there is provided a pneumatic accumulator 50 which serves to maintain a body of the oil under pressure. Between the accumulator and the fuel nozzle there is also provided a cut-off valve 52 by means of which the flow of oil to the nozzle may be entirely cut off. The pneumatic accumulator serves not only to maintain a balanced pressure on the liquid fuel during the time the pump is functioning to supply the fuel under pressure but also serves as a reservoir from which fuel may be drawn under pressure to start the engine. The amount of oil supplied to the nozzle is controlled in any suitable manner as by a valve 54 arranged in a bypass 56 extending around the ump.

The invention contemplates that the oil shall be sprayed from the fuel nozzle at a substantially constant velocity irrespective of the engine speed and irrespective of the rate at which fuel is supplied to the nozzle. This regulation of fuel spray velocity is obtained by providing a needle valve 58 within the nozzle whereby the discharge capacity of the nozzle may be varied in conformity with the amount of fuel supplied to the nozzle chamber 44. To this end the stem of the valve is enlarged as indicated at 60 in order to provide a shoulder 62 against which the pressure of the oil received into chamber 44 may react, this reaction tending to force the valve away from its seat in the nozzle. The tendency of the valve to move away from the seat under the pressure of the oil is opposed meme? by a spring 64 disposed between the lower end of the valve stem and a fixed abutment ofbracket 66. It is also preferred that the angle included by the ti of the valve 58 be less than that included y the walls of the chamber 44 ad'acent the valve seat as indi cated at 68. y this arrangement the oil pressure within the chamber 44 exerts additional downward push on the valve stem.

While the t pe of nozzle valve indicated in Fig. 1' is pre erred, nevertheless, the invention is not limited to this particular type of valve. If desired, the nozzle valve may he of the type shown in Fig. 2 which is to say the valve may be mechanically operated in conjunction with the operation of the fuel supply controllin valve 54. As indicated in ig. 2, the v ve may be provided with screw threads 55 so that when it is turned,

" 'ts position may be adjusted in the fuel nozzle as will be readily understood. The valve may be turned by any suitable means as by a rack and pinion generally indicated at 61, the rack being connected with an operating arm 55 of the valve 54. The fuel nozzle valve 18 is so coordinated with the fuel supply controlling valve 5% that when the latter is opened the passage through the fuel nozzle will be correspondingly decreased, and vice'versa.

As has been previously indicated, air is drawn into the mixing chamber by the suction-of the engine and theaspirating effect of the fuel spray issuing from the fuel nozzle. In the arrangement shown in the drawing, counterclockwise rotation of the air valve 26 tends to open it while a similar directional rotation of the fuel supply controlling valve 54 tends to close it. In order that the amount of air flowing to the mixing chamber may be properly co-ordinated with the rate of fuel supply, the fuel supply valve 54 and the air valve 26 are connected by suitable linkage. As shown, an arm 80 extends from the valve 26 and from this arm extends a rod 82 which is connected with the arm 55 of the fuel valve 5 through intermediate mechanism which preferably includes the following elementsto wit: Extending from the arm 55 of the valve 54: is a rod 84 which is connected to a swingable cam 8'6, this cam cooperating with another swingable cam 88 which is maintained in contact with the cam 86 as by a spring 90. Extending from the cam 88 is a rod 91 which is connected to a floating lever 92 to which the previously mentioned rod 82 is also connected, this lever 92 being under the control of an engine driven overnor generally indicated at 94, the driving shaft for the governor being indicated at 96. As the speed of the engine increases the governor 94 pulls the floating lever 92 toward the right as shown in the drawing, or in other words moves it in a clockwise direction to increase the opening of the air valve 26. It will now be seen that the connections between the air valve 26 and the fuel su ply controlling valve 54 are such that when t e valve 5t is moved in a counterclockwise direction to increase the fuel delivery by preventing the fuel from by-passing the pump, the air valve 26 will be correspondingly opened. The cams 86 and 88 are calibrated to coordinate the relative angular movements of arms 55 and 80 and the corresponding openings of valves 54 and 26 to provide the predetermined optimum-mixture ratio,

The drawing is intended to illustrate not so much the actual construction of all the various elements as to illustrate the general combination of the elements and it is therefore'within the scope of the invention to make various structural changes without departing from the spirit of the invention as defined in theappended claims.

I claim:

1. In a fuel feeding system for internalcombustion engines of the Otto type, a mixing-chamber into which fuel and air are received prior to their passage to the engine manifold, an air-conduit through which air may enter the mixing-chamber, means for regulatin the amount of fuel supplied to said cham er, and means under the combined control of the engine speed and the fuel flow regulating means for controlling the flow of air to the mixing-chamber, whereby to maintain a predetermined ratio of fuel to air in the mixing-chamben 2. A fuel feeding system for internal-combustion engines of the Otto type including a nozzle through which fuel may be sprayed, a mixing-chamber into which fuel and air are received'prior to their passage to the engine manifold, an air-conduit through which air may enter the mixing-chamber, means cooperating with the fuel-nozzle for maintaining a predetermined spray velocity at the fuel nozzle irrespective of the amount of fuel supplied to the nozzle and means under the combined control of the engine speed and the fuel flow regulating means for controlling the flow of air to the mixing-chamber whereby to maintain a predetermined ratio of fuel to air in the mixing-chamber.

- 3. A fuel feeding system for internal combustion engines of the Otto type comprising in combination with the intake manifold of the engine, a nozzle through which fuel may be sprayed, a mixing chamber into which the spray is received prior to its passage to the engine manifold, a conduit through which air may enter the mixing chamber, means for maintaining the fuel supply under high pressure, means for regulating the flow of fuel to the fuel nozzle, means for regulating the discharge capacity of the fuel nozzle in accordance with the rate of fuel supply whereby to maintain a predetermined minimum fuel-spray-velocity at the nozzle irrespective of the rate at which fuel is supplied thereto, and means under the combined control of the engine speed and the fuel flow regulating fuel and the amount of air delivered to said chamber and automatic means for increasing the flow of air compared to the flow of. fuel with increasing speed of the engine.

5. The combination with the intake manifold of an internal combustion engine of'the Otto type of a mixing chamber, a nozzle arranged to deliver a spray of fuel into one end of said chamber, an air duct having an air passage connecting to said duct and surrounding the axis of said nozzle, said passage decreasing in cross section proportion ally to the distance from said duct, said cha1nher being connected to said passage by holes set around and in an inclined relation to the nozzle, whereby the air is introduced into the mixing chamber with a whirling motion.

6. The combination with the intake manifold of an internal combustion engine of the Otto type of a mixing chamber, a nozzle arranged to deliver aspray of fuel into one end of said chamber, an air duct having air passage connecting to said duct and surrounding the axis of said nozzle, said passage decreasing in cross section proportionally to its distance from said duct, the wall of said chamber being connected to said passage by holes set around said nozzle.

7. The combination with the intake manifold of an internal combustion engine of the Otto type, of a mixing chamber, a nozzle arranged to deliver a spray of fuel into one end of said chamber, an air duct and a passage connected to said duct and surrounding the axis of said nozzle, the Wall of said chamber having holes set around said nozzle and connecting said chamber with said passage.

8. The combination with the intake manifold of an Otto engine of a fuel nozzle, a mixing chamber between said nozzle and manifold, aconduit for admitting air to the mixing chamber, a fuel pump for supplying fuel under high pressure to the nozzle, a by-pass around the pump whereby the amount of fuel flowing to the nozzle may be controlled, a valve within the fuel. nozzle operable to regulate the discharge capacity of the nozzle in a manner to maintain the fuel discharge velocity above a "predetermined minimum, a valve operable to regulate the air delivery capacity of the air conduit, and operator controlled means whereby the by-pass and the air valve may be regulated simultaneously.

9. In a. carburetor, a nozzle surrounded by air vanes controlled by operator and automatic means. I

10, In a carburetor, a nozzle surrounded by air vanes controlled by operator and automatic means through themedium of co-ordinated differential cams.

11. An apparatus comprising a nozzle, a pump for supplying liqglid fuel thereto, an air duct, a mixing cham differential cams through the medium of which said fuel pump and said air duct are controlled.

12. An apparatus comprising a nozzle, a pump for supplying liquid fuel thereto, an air duct, a mixing chamber, and coordinated differential cams through the medium of which the fuel supply from said pump and the flow of air through said air duct are manually and automatically controlled.

13. An apparatus comprising a fuel and air mixing chamber, a nozzle for spraying fuel into said mixing chamber, a spring loaded valve controlling said nozzle, a fuel supply line between said pump and said nozzle, means in said supply line for maintaining the liquid fuel at constant pressure, and means including coordinated differential cams controlling the supply of air to said mixing chamber and the supply of fuel to said nozzle.

14. An apparatus comprising a fuel and air mixing chamber, a nozzle for spraying fuel into said mixing chamber, a fuel supply line between said pump and said nozzle, means in said supply line for maintaining liquid fuel at constant pressure, and means including coordinated differential cams adapted to be manually and automatically actuated for controlling the flow of air to said air mixing chamber and the flow of fuel to said nozzle.

In testimony whereof I afiix my signature.

ROBERT EARLL BRUOKNER.

er, and coordinated 

